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Biomedical subjects

C S David

Publications and source records attributed to C S David.

At least 199 records · Page 11Linked to original sources
PubMed1987

Identification of I-E alpha genes in H-2 recombinant mouse strains by F1 complementation.

Nine recombinant H-2 mouse strains with crossovers in the I region between I-E-negative haplotypes f,q and I-E-positive haplotypes p,k were examined for I-E expression by microcytotoxicity dye exclusion assay. These recombinants were found to be negative for I-E expression. There are two possible genotypes in these recombinant mouse strains that could result in lack of I-E expression. Recombinants with crossovers between the E alpha gene and the S region would have both nonexpressed I-E alpha and beta genes (E beta fE alpha f, E beta qE alpha q) and recombinants with crossovers between the E beta and E alpha genes would have a nonexpressed E beta gene (E beta f or E alpha q) and a functional E alpha gene (E alpha k or E alpha p). To distinguish between these possible genotypes these recombinants were crossed to B10.A(4R), which carries a functional E alpha k gene but is I-E-negative due to a nonexpressed E alpha b gene. F1 mice were examined for transcomplementing I-E molecules by immunoprecipitation of 3H-leucine-radiolabeled detergent lysates of spleen cells with a monoclonal I-E antibody (14-4-4). Detection of a transcomplementing I-E molecule was confirmed by immunoprecipitation with a monoclonal antibody (H9-14.8) specific for the I-Ek beta polypeptide chain derived from B10.A(4R) and by tryptic peptide map comparisons. Five recombinant mouse strains were able to complement with B10.A(4R) in F1 mice to generate a transcomplementing I-E molecule, and thus have an expressed I-E alpha gene (E alpha k or E alpha p). Four recombinants did not complement with B10.A(4R) in the F1 expression of I-E molecules, and thus have nonexpressed I-E alpha genes (E alpha f or E alpha q).

Animals↗
PubMed1987

Human retroocular fibroblasts in vitro: a model for the study of Graves' ophthalmopathy.

Orbital connective tissue and extraocular muscles are histologically abnormal in patients with Graves' ophthalmopathy (GO). Although extraocular muscles have been extensively studied as a target for autoimmune attack in the disease, no system has been available to study retroocular fibroblasts in GO. We developed a technique to isolate fibroblasts from minced explants of connective tissue removed in the course of transantral orbital decompression surgery for GO. Postmortem specimens from individuals without evidence of thyroid disease were obtained from the same anatomical site. Confluent cells could be passaged at least 10 times with stable morphology and frozen with greater than 75% viability. An enzyme-linked immunosorbent assay was used to study the in vitro binding of serum immunoglobulin G (IgG) to these cells. We found no difference in the degree of specific binding between GO cells and cells from normal individuals. However, there was significantly greater binding of IgG from GO sera than of that from normal serum to retroocular GO fibroblasts. These results suggest that serum IgG autoantibodies against normal retroocular fibroblasts are present in some GO patients.

Adult↗
PubMed1986

Mapping of a second recombination hot spot within the I-E region of the mouse H-2 gene complex.

The crossover points of nine intra-I region recombinant mouse strains were determined by restriction fragment analysis. The recombinants were examined for the presence of k and p haplotype specific DNA restriction endonuclease sites. These restriction sites were a Sac I site between the E beta and E beta 2 genes, a Hpa I site within the E beta 2 gene, and a Rsa I site approximately 1 kb to the right of the E alpha gene. Seven of the recombinants were found to have crossovers between the Hpa I and the Rsa I site. This analysis suggests that a recombination hot spot exists within this segment. This segment is approximately 12-14 kb, and contains the E alpha gene and the intervening sequence between the E beta 2 and E alpha genes.

Animals↗
PubMed1986

Susceptibility to Theiler's virus-induced demyelination. Mapping of the gene within the H-2D region.

Demyelination induced by Theiler's virus was examined in mouse strains with congeneic recombinant haplotypes. Light and electron microscopy of spinal cord sections from mice with s, q, v, p, and f H-2D alleles showed perivascular inflammation and primary demyelination. The presence of susceptible haplotypes in the K or I region did not correlate with pathologic abnormalities. The Qa, Tla, PgK, and UpG genes did not appear to be critical in determining susceptibility to disease. However, mutation in the H-2D genes altered the susceptibility to virus-induced demyelination. B10.D2dm1 mice, which have deletions in the 3' end of Dd and the 5' end of Ld, showed prominent demyelination and clinical deficits. In contrast, BALB/c-dm2, which have a deletion of the entire L gene, showed no pathologic changes. Central nervous system virus titers correlated with susceptibility to demyelination; both resistant and susceptible strains had a strong humoral immune response to the virus. The findings in the congeneic recombinant mice and in mice mutant in the H-2D region strongly suggest that at least one of the genes critical for determining virus-induced demyelination maps to the 3' end of the H-2D gene.

Animals↗
PubMed1986

Recombination hot spots within the I region of the mouse H-2 complex map to the E beta and E alpha genes.

Recombinant mouse strains with crossovers in the I region of the H-2 major histocompatibility complex were examined by restriction fragment analysis for the presence of polymorphic restriction sites within the E beta and E alpha genes. Nine recombinant mouse strains were shown to have crossed over within a 5 kb DNA segment that contains the large intron between the second and third exons of the E beta gene. These results are in accord with previous studies mapping a recombination hot spot within this gene. Seven recombinant mouse strains between the p and k haplotypes were shown to have crossed over in a 6 kb segment within the E alpha gene. These results show the existence of a recombination hot spot within the E alpha gene. Comparison of the H-2 haplotypes involved in these two recombination hot spots suggests that a specific DNA sequence in b, s, f, and q haplotypes may act to promote recombination in the E beta gene and a specific DNA sequence in the p haplotype may act to promote recombination in the E alpha gene.

Animals↗
PubMed1986

Serological confirmation in Ia mutant B6.C-H-2bm12 of gene conversion.

Recently it has been suggested that a short segment of the DNA sequence of the Ia beta gene in the mutant B6.C-H-2bm12 (bm12) is derived from the Eb beta gene by a gene-conversion-like mechanism, and that the same segment is also seen in the Ek beta gene. To obtain serological evidence for this idea, we produced an antibody against the "new" determinant on the I-Abm12 molecule by immunizing A.BY mice with bm12 cells. After absorption with B6 lymphocytes to remove antibodies against background antigens, the antisera lysed bm12 cells. Typical Ia peaks were obtained by immunoprecipitation. The absorbed antiserum reacted with B10.A (Ek beta), B10.A(5R) (Eb beta) and B10.S(9R) (Es beta), but not B10. The unabsorbed antiserum is specific for Ia when tested on A background mice. The antiserum lysed spleen cells of Ik strains (A/Sn, A.AL, A.TBR1, and A.TFR1) but not Ak strain, A.TBR13 (KsAkEbSbDb), confirming the presence of antibodies against the I-Ek molecule. This anti-serum also lysed the cells from (A.BY X A.TFR5)F1, which expresses the transcomplementing Eb beta Ek alpha molecule and from the (A.SW X A.TFR5)F1 which expresses the transcomplementing Es beta Ek alpha molecule. These data are consistent with DNA sequence analyses, and show the existence of a determinant (Ia.51) generated in the bm12 mutant by a gene-conversion-like event that is also present in the I-Ek, I-Eb, and I-Es beta polypeptide chains.

Animals↗
PubMed1986

Collagen-induced arthritis and pregnancy in mice: the effects of pregnancy on collagen-induced arthritis and the high incidence of infertility in arthritic female mice.

Collagen-induced arthritis (CIA) in mice is a model of inflammatory polyarthritis that has many features similar to human rheumatoid arthritis. In rheumatoid arthritis, pregnancy leads to amelioration of the disease while exacerbation develops after delivery. We used the CIA model to elucidate the role of pregnancy on disease and vice versa. The onset of arthritis in pregnant mice was delayed in the B10.RIII strains immunized with native porcine type II collagen 7-12 days prior to syngeneic [B10.RIII (susceptible to CIA) X B10.RIII] and allogeneic (B10.RIII female X B10.K male that are CIA resistant) pregnancy. In contrast, when mice were immunized on days 1-6 of pregnancy, the onset of arthritis was earlier as compared with controls. In addition, once the mice developed CIA after delivery, the disease showed markedly rapid progression as compared to the control immunized group. Humoral immune responses to type II collagen showed significantly decreased levels on day 14 (at late stage of pregnancy) both in syngeneic and allogeneic postmating immunized pregnant mice. The same effect was also seen in allogeneic premating immunized pregnant mice on day 21 (at mid-stage of pregnancy). The levels of these antibodies increased after delivery. Subclasses of IgG1 and IgG2a antibodies to type II collagen were suppressed during pregnancy. In the pseudopregnant group, these antibodies showed decreased levels on day 14, but did not differ from the control groups on day 21 and 28. Some immunoregulatory changes may play a role in these alterations in pregnant arthritic mice. In comparison to the effects of syngeneic (susceptible X susceptible) pregnancy on CIA, allogeneic (susceptible female X resistant male) pregnancy seemed to be beneficial for the affected individuals. Litter size and mean birth weight were not affected by immunization of type II collagen. After onset of CIA, both syngeneic and allogeneic matings failed to produce offspring in arthritic female mice. The estrus cyclicity was highly disturbed in arthritic female mice and gonadotropin stimulation in arthritic mice induced significantly less ova in oviducts and maturing follicles as compared to nonarthritic controls. Immunological factors yet to be elucidated may be involved in this ovarian dysfunction.

Animals↗
PubMed1986

Electrophoretic analysis of liver neuraminidase-1 variation in mice and additional evidence concerning the location of NEU-1.

Neuraminidase-1 (NEU-1) is one of two neuraminidase isozymes which can be detected electrophoretically in mouse liver extracts. The inheritance of variation in NEU-1 and the linkage relationships of the gene controlling this variation were studied through a backcross analysis involving the SM/J and MA/MyJ inbred strains, and by examination of NEU-1 phenotypes in three congenic strains: B10.SM, B10.SM(22R) and B10.RVB. The data indicate that NEU-1 is controlled by Neu-1, a gene previously identified by its effect on total liver neuraminidase activity in whole tissue homogenates. Analysis of the congenic strains revealed identical low activity (SM/J-type: Neu-1a/Neu-1a) NEU-1 phenotypes in all three strains. This indicates that Neu-1 lies in the segment of the SM/J-derived H-2 region that is common to all three strains: H-2E alpha to H-2D. In addition, we examined the relationship between NEU-1 and phenotypic variation in liver acid phosphatase (AP; for which a new typing method is described) and linkage order among several other enzyme-coding genes linked to H-2. In all animals that could be scored confidently for AP, the NEU-1 and AP phenotypes were concordant, adding support to the hypothesis that both phenotypes are controlled by Neu-1. Recombination rates among six H-2-linked marker loci were unexpectedly low, but were sufficient to verify the position of Upg-1 as the telomeric flanking marker relative to Glo-1, H-2 (C4), Neu-1 (Apl), Ce-2 and Pgk-2.

Acid Phosphatase↗
PubMed1986

Partial suppression of Theiler's virus-induced demyelination in vivo by administration of monoclonal antibodies to immune-response gene products (Ia antigens).

In vivo administration of monoclonal antibody reactive with major histocompatibility complex-encoded Ia molecules (I-As) partially suppressed inflammation and demyelination in the spinal cord of SJL/J (H-2s) mice persistently infected with Theiler's murine encephalomyelitis virus. Demyelination was decreased if antibody was given at the time of virus inoculation or after inflammation had been established in the spinal cord. The decrease in demyelination was independent of isolation of infectious virus from the CNS or of serum titers of immunoglobulin to purified viral antigen. Thus, Theiler's virus-induced demyelination is mediated, in part, by immune cells that carry Ia class II molecules.

Agglutination Tests↗
PubMed1986

Molecular heterogeneity of I-Ab molecules: analysis of I-Ab subsets with monoclonal antibodies.

In the mouse there are two Ia molecules, A and E, which are encoded by two alpha genes and two beta genes. However, previous studies from this laboratory suggested the existence of multiple forms of Ia molecules. In this report, we have investigated the molecular heterogeneity of Ab molecules by isolating and analyzing subpopulations of Ia molecules. By using monoclonal antibody affinity columns, we have isolated four distinct subpopulations of Ab molecules. These subpopulations representing a significant fraction of the total A molecules were negative for determinants recognized by one or more anti-Ab monoclonal antibodies. Possible mechanisms of the origin of these molecules are discussed.

Animals↗
PubMed1985

Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. I. Its regulation by I-A gene products.

It has previously been demonstrated that within 6 hr after immunogenic stimulation the serum of mice contains a unique form of immunogenic antigen which represents complexes of Ig and antigen. The complexes are known to be strongly cytophilic for Ly2+ Ia+ FcR+ T cells and markedly enhance the IgG response. Anti-I-A treatment of mice suppresses the IgG antibody response and results in the generation of antigen specific T suppressor cells (Ts). Furthermore, anti-I-A treatment blocks the induction of the complexes and abolishes the enhancing effect the complexes exert on the IgG antibody response. The 6-hr cytophilic complexes were shown to block the function of Ts and allow a normal IgG response to take place; therefore, they act as mediators of a novel T-cell pathway called antisuppression. The blocking of the induction of the antisuppressor complexes by anti-I-A antibody was at least in part due to an effect on T cells. In conclusion, products of genes of the I-A subregion of the MHC control the activation early after immunization of a T-cell pathway which is called antisuppression since its major function is interference with the expression of suppression. Its early induction (within 6 hr) suggests that antisuppression may play a pivotal role in determining between immunity and unresponsiveness.

Animals↗
PubMed1985

Proximity of the Mep-1 gene to H-2D on chromosome 17 in mice.

The Mep-1 gene on chromosome 17 in mice controls the activity of meprin, a kidney brush border metalloendopeptidase. Most inbred mouse strains of the k haplotype (e.g., CBA, C3H, AKR) are markedly deficient in meprin activity; these mice carry the Mep-1b allele. Mouse strains in which meprin activity levels are normal are designated Mep-1a. Studies using congenic and recombinant strains mapped the Mep-1 gene telomeric to H-2D near the Tla gene. To further study the relationship between the major histocompatibility complex and Mep-1, a linkage study was conducted. Mep-1a F1 hybrids [C3H.A (KkDd) X C3H.OH (KdDk)] were backcrossed with Mep-1b C3H.OH (KdDk) parents. The progeny were assayed for H-2D markers, Pgk-2 isozymes, and meprin activity. Recombination between H-2D and Mep-1 occurred in 6 out of 284 mice, a crossover frequency of 2.1%. Mep-1 is therefore 2.1 crossover units telomeric to H-2D and approximately 0.6 crossover units from Tla. The Mep-1 locus provides a new genetic marker for the future mapping of this important area of the mouse genome.

Amino Acids, Sulfur↗
PubMed1985

Characterization of the in vitro murine T-cell proliferative responses to murine and human thyroglobulins in thyroiditis-susceptible and -resistant mice.

The in vitro proliferative response to autoantigenic mouse thyroglobulin (MTg) of lymph node cells (LNC) from thyroiditis-susceptible (high-responder) CBA/J (H-2k) mice was further characterized. The relatively weak response was enhanced by adding irradiated spleen cells from normal syngeneic mice to cultures of responding LNC. Furthermore, the adjuvant used for immunization was found to influence the magnitude of the response. Results of experiments varying both the adjuvant and the route of immunization (footpad versus subcutaneous) demonstrated that marked proliferative response to MTg in vitro was not necessarily a predictor of the severity of disease. However, the capacity to proliferate in response to MTg correlated with disease susceptibility, as reported previously. The response to MTg was dependent on Thy-1+, Lyt-1+2- cells and was inhibited by monoclonal I-A antibodies. Thus, proliferation is mediated by T cells of the helper/amplifier phenotype recognizing the autoantigen in association with Ia molecules. The determinants on human thyroglobulin (HTg) and MTg stimulating the proliferative responses of LNC from thyroiditis-susceptible and thyroiditis-resistant (low-responder) BALB/c (H-2d) mice were found to differ. Cells from resistant mice proliferated only in response to foreign determinants on HTg and not to shared or mouse-specific epitopes of MTg, whereas susceptible mice had T cells reactive to shared determinants expressed on MTg and HTg as well as to foreign determinants on HTg.

Adjuvants, Immunologic↗
PubMed1985

Type II collagen-induced arthritis in mice. IV. Variations in immunogenetic regulation provide evidence for multiple arthritogenic epitopes on the collagen molecule.

Type II collagen from six mammalian species was investigated for the capacity to induce an immune response and collagen-induced arthritis (CIA) in C57/B10 congenic mouse strains. H-2q haplotype mice were susceptible to chick, bovine, deer, rat, and human type II collagen, but were resistant to arthritis induced by porcine type II collagen. H-2r haplotype mice only developed CIA in response to bovine, deer, and porcine collagen. High antibody responses in the absence of disease, directed against a specific type II collagen, were observed in many independent haplotypes. The cross-reactive capacity of different antisera to the various collagen species was studied. The data support the existence of two arthritogenic and multiple nonarthritogenic epitopes on the type II collagen molecule.

Animals↗
PubMed1985

The Hb-2d cross-reactive idiotype. A common idiotype expressed by monoclonal and polyclonal antibodies to human haemoglobin.

Hb-2d is a monoclonal antibody of B10.D2 origin that is specific for the beta chain of human adult haemoglobin (HuHb-beta). Polyclonal anti-idiotypic sera to Hb-2d were produced in B10.D2, SJL/J and BALB/c mice. Using anti-idiotypic sera from SJL/J it was observed that Hb-2d expresses a cross-reactive idiotype (CRI) also found on both polyclonal and monoclonal antibodies to HuHb. Polyclonal antisera against HuHb-beta from H-2 congenic mice on the C57BL/10 (B10) background contained antibodies expressing the Hb-2d CRI; these antisera, however, contained little if any antibody to the antigenic determinant on HuHb-beta recognized by Hb-2d. Polyclonal antisera to HuHb-beta from the strains A.CA, A.SW, C3H.OL, BALB/cByJ, DBA/2 and SJL/J contained lower, but nevertheless detectable, amounts of antibody expressing the Hb-2d CRI. Unlike B10-H-2 congenic mice, antisera from the strains A.CA, A.SW and BALB/c bound to the same or a closely associated determinant as that recognized by Hb-2d. Two anti-HuHb monoclonal antibodies, Hb-48a and Hb-53a, both derived from B10-H-2 congenic mice, were shown to possess at least part of the Hb-2d idiotype. These antibodies are specific for epitopes on the human haemoglobin alpha chain (HuHb-alpha). It would appear, therefore, that Hb-2d possesses a CRI that is carried by antibodies to various antigenic determinants on HuHb. The linkage of these different antibodies by the CRI may allow for a common regulatory pathway.

Animals↗
PubMed1985

Demyelination induced by Theiler's virus: influence of the H-2 haplotype.

Demyelination induced by Theiler's virus was examined in nonrecombinant H-2 congeneic strains of mice on common backgrounds expressing independent haplotypes. Light and electron microscopy of spinal cord sections from mice with s, f, p, r, v, or q haplotypes on a C57BL/10 background showed perivascular inflammation and multifocal areas of demyelination in the white matter. The demyelination in these mice was usually associated with clinical neurologic deficits. In contrast, mice with identical genetic backgrounds but b, k, or d haplotypes showed no pathologic or clinical abnormalities. Qa or Tla haplotypes did not appear to influence demyelination. The observations support the hypothesis that susceptibility to Theiler's murine encephalomyelitis virus-induced demyelination is influenced by genes that are linked to the H-2 complex. The findings suggest that the demyelination may be mediated by immune cells rather than being a direct cytolytic effect of virus on oligodendrocytes.

Animals↗